Ender 3 Filament Runout Sensor for Z limit switch

thingiverse

# Filament Runout Sensor After installing the BLTouch on my Ender 3, I ended up with the Z Axis limit switch in hand. It becomes quite useless since it's replaced by the BLTouch. I had seen some designs for filament runout sensors online, but most used a custom limit switch and Bowden tubing. Moreover, none that I found had a mount for the Ender 3. So, I used FreeCAD to make myself a filament runout sensor that reuses the Z axis limit switch entirely. What you plug it into (Pin 29 or Raspberry Pi Octopi detection) is up to you! You will need to have flashed your 3D printer with Marlin including advanced pause for this to work! But if you already have ABL, you've probably done something like this before, so you should be fine. ## Instructions 1. Print using a small layer height for better filament sliding behavior. 2. Insert the Z limit switch, making sure the bottom goes where the little rails are. It won't fit if it's not in the right orientation! There's no need to force it. 3. Put the top cover on and clip it using the printed clips and rail guides. 4. Unscrew the two screws holding the Z_axis guide, insert the runout sensor, and screw back the Z axis guide. 5. Plug into what you wish - FYI, left to right pins are: Signal, Ground, 5V 6. Enjoy! ## Extras I've included the FreeCAD design files for anyone to modify and remix! You don't like the attachment? Do it differently!